The present invention is considered an improvement of and a departure from such prior strapping machine devices as for example disclosed in U.S. Pat. No. 3,667,378 to Van de Bilt entitled Wire or Band Strapping Machine. In the Van de Bilt patent is disclosed a device for a strapping machine in which a band is passed about a looped path. A first pair of rollers functions as a feeding means for the band and a second pair of rollers functions as a retraction means for the band. A linearly reciprocating tension device is positioned between the feeding rollers and the retraction rollers. The feeding rollers are located nearer to the closed loop than are the retraction rollers with respect to the direction of movement of the wire or band.
That device, while generally acceptable for the purposes intended, required a rather long stroke by the linearly reciprocating tension gripper. It required a gripper which was adapted to positively grasp the strap and to move the strap in a direction substantially parallel to the direction of the strap travel through the tension gripper. Thus, the strap was taken up only to the same degree that the tension gripper was extended. In other words, if the tension gripper were extended by three inches, then the net strap take-up would be limited to a maximum of three inches. This requires a relatively large amount of room in which the tension gripper cylinder may be reciprocated during the gripping operation. Because of the telescoping cylinder and piston rod arrangement, the total room required to accommodate the tension gripper was multiplied.